Heat resistant liquid resin composition from phenol, formaldehyde and dicyandiamide, and process for making same



United States Patent 43mm HEAT RESISTANT RESIN COMPOSITION FROM PIDENOL, FORMALDEHYDE AND DI- CYANDIAMIDE, AND.PROCESS FOR MAKING Jerome'J. Mestdagh, Springfield, and Charles A. Magarian, Hampden, Mass.,'assignors to Monsanto Chem!- cal Company, St. Louis, M0,, a corporation of Dela ware No Drawing. Filed Mar. 17, 1958, Ser. No. 721,693 7 Claims. (Cl. 260-293) The present invention is directed to providingfusible water-dilutable liquid resin compositions which are heat resistant when cured and more particularly toresin compositions comprising mixtures of dicyandiamide-formaldehyde and phenol-formaldehyde partial condensatesl Phenol-formaldehyde liquid resins are widely used as binders in various applications. In practice, these resins are initially applied in liquid form to the materials-which are to be adhered or cohered, as for example glass fibers, and then subjected to. thermosetting conditions to convert the mass to solid form. A distinct disadvantage has accomplished use of these resins in certain technical areas resulting from their comparatively low heat resistance and flame retardance. Various attempts have been made to remedy this situation but with little success. In general, the attempts can be described as directed to introducing or incorporating nitrogeneous components such as cyanamides, having the desired thermal qualities into the resins. One such process which is directed to incorporating nitrogeneous material into these resins prescribes'reacting an aliphatic aldehyde with phenol under alkaline catalytic conditions to form a partial condensation product which is in turn interreacted with a cyandiamide such as dicyandiamide, melamine or the like. These expedients, however, in turn give rise to further problems. More particularly, while the introduction of these materials does enhance the qualities of fire resistance and flame retardance of the cured material in attaining this end, the 'water-dilutability properties otherwise present and which facilitate their initial application, are sacrificed. In addition, loss is magni fied if the resins, so treated, are allowed to stand for any period prior to application. As a result, and for the most part, the introduction of the nitrogeneous material is carried out immediately prior to application. It has now been discovered that single package water-dilutable resins can be provided through exercise of a peculiar process.

Accordingly, it is a principal object of the present in I vention to provide water-dilutable liquid resinswhich are'heat resistant and flame retardant when cured.

Another object is to provide such resins containing phenol-formaldehyde thermosetting resins.

added and the mixture is heated to 60-70 C. When the dicyandiamide becomes dissolved or about the time the Patented Oct. 17., 1961 ice the free formaldehyde in the reaction mixture drops to a predetermined content of approximately 12.2% by weight of the reaction mixture as determined by the hydroxylamine hydrochloride test. The product is then cooled to -50 C. and the pH adjusted to 7.5-8.0by the addition of 10% hydrochloric acid. The reaction mixture at this point is considered to be infinitely waterdilutable; i.e., 24 or more volumes of water may be mixed with '1 volume of the reaction mixture at a temperature of 24-26 C. without causing the mixture to exhibit haziness or milkness. Sixty-five parts of dicyandiamide are then reaction mixture reaches 60-70 C., the reaction is arrested by cooling to 20-30 C. The product can be diluted in 24 volumes of water without exhibiting 'cloudinessand accordingly is considered to be infinitely Water-'dilutable. When tested it is found to contain in mol ratio approximately 2.2 mols of formaldehyde reacted with each mol of phenol and 1.6 mols of formaldehyde reacted with each mol of dicyandiamide using the hydroxylamine hydro: chloride test for residual free formaldehyde. The testis j run before and after the addition of the dicyandiamide.

The diluted product is allowed to'stand for a period of.

24 hours and no haziness or milkiness is observed. Another portion of the above product is retained for a period of several weeks at a temperature of 0-l0 C. and when tested for dilutability exhibits substantially the same standard as above.

Another portion of the above product is diluted in water to about 18% solids. This solution is sprayed onto a matrix of glass fibers in an amount equal to about 8% by weight of cured resin. The assembly is subjected to drying conditions by forcing a volume of air heated at 100 F. through the same for a period of 3 minutes. The dried assembly is placed in a mold and cured for 2 minutes at 400 F. to form semi-cylindrical sections of Z-inch thickness, 3 feet in length and having an interior diameter of 2 Other objects of the invention will in part-be obvious and will in part appear hereinafter.

These and other objects can be attained by reacting dicyandiamide and formaldehyde in the presence of a fusible alkaline catalyzed phenol-formaldehyde water-dilutable reaction mixture to form in admixture with said reaction mixture, a water-dilutableliquid partial condensate 'of dicyandiamide and formaldehyde.

The following examples are given in illustration of the invention. Where parts are mentioned,

parts by weight are intended unless othrewise prescribed.

Example I I To a reaction vessel. fitted with an agitator, a'heater and a condenser adapted for refluxing under vacuum conwith formaldehyde.

inches. The sections are applied to the exterior of a 2- inch diameter iron pipe and wound with asbestos-treated canvas and clamped When the pipe is subjected to interior temperatures up to 600 F., the material does not exhibit punking or lose its insulation properties.

When commercially available phenol-formaldehyderesins are utilized in accordance with the preceding, punking and degradation of" the insulating qualities are manifest when subjected 'to temperatures in excess of 300 F.

Example II To the reaction vessel of Example I, add parts of phenol, 280 parts of 37% formalin, and 3.7 parts of so dium hydroxide. The reaction is carried out as above until the-free formaldehyde drops to approximately 8.8%

byweight of the reaction mixture. After cooling and adjusting the pH as disclosed above, 40 parts of dicyandiamide are added and the reaction continued until the dicyandiamide is in solution. The product contains in mol ratio approximately 2.2 mols of formaldehyde reacted with each mol of phenol and 1.4 mols of formaldehyde reacted with each mol of dicyandiamide and is dilutable with 24 volumes of water.

V I I I Example III p The procedure set forth in Example I is again followed with the exception that pH of the reaction mixture is adjusted from 8.5-9.0 to 7.5-8.0 with 10% hydrochloric acid after the addition and reaction of the dicyandiamide The product which results can be diluted in 24 volumes of water without exhibiting hazing, etc.

Example IV The procedure set forth in Example I is again followed half volumeof. water-accompanied by stirring; .Upon termination .of stirring milkiness is exhibited indicating not dilutablewith-watersz with the exception that aftera'ddition of'the dicyandi amide the mixture is reacted at-70 C. for 30 minutes; The water dilutabi-lity of this product is about 10 to 1, which. is considered about the minimum required for a highly water-dilutable resin. f

amp e V-.. w. The; reaction yesselis again charged with loo-parts of phenol, 340, parts of '3 7%*forma1in and 3.7 parts of sodiumhydroxidet; I'he mixture;.-is;-allowedto'= react by. providing? a vtemperature. ofabout-70 1C; Reaction is confirmed-until the free formaldehyde; in the reactionrn i rtur e approaches a- :predetermined lcontent :ofapproximately ,-1 2.2,%--by;weight of thereaction mixture-as dee terminedby the-hydroxylamine hydrochloride test. {The .product is then cooled to40:.50 C. andthepHAadjusted' to- 7.5 8,0:!by the-,addition of 10%.- hydrochloric acid. The reaction mixture at this point is -'-infinite1y-water-- 2 dilutable; aonewolumeportion thereof :can :be diluted with- 2l4r v olumes of water without haziness or-milkiness' beiug exhibited.r .Sixty-five parts (of: dicyandiamide are then added to themixturerand the whole'isallowed to re-' flux at: atmospheric conditions or :about. 100, C.,"--for a period of -3.0 minutesirfollowed-by cooling to 2(t-30 C. A portion of the resulting .product is mixedlwit-h a.one+.

that theproduct has'less than 0.5 water-'dilutability. Another portionof the product is. allowed :to stand fora period of :12 hours andwhen then observed-.is-found to a have separated;into. -two phases, :awaterphase floating s on a resinous phasa'the latter is determined-asheing a .copolymerof; phenol-forma1dehyde dicyandiamidez' The, foregoing: indicates thatthe phenol-formaldehyde:1 condensate. will .interreact with the dicyandiamide to form a non-dilutable copolymer.unlessa'critical time-tempera ture relationship, ;isfollowed particularly. after, introduction of the dicyandiamide. to thereaction-medium. The process of-v the present invention is directed to pro-1 viding water-dilutable ..fusible -liquid TITSi11= =-compositions which whencured are heat-resistant; punk-resistant and flame, retardant. It involvesaeacting,dicyandiamide 'andai formaldehyde in. thelpresenceof. an -alkaline=catalyzed Y reaction .mixture of :phenoL-formaldehyde to produce az water-dilutable fusible admixture-total condensates? of phenol-formaldehyde and dicyandiamiderformaldehyde. s The process can-be initiated by reactinga first: charge of phenol with formaldehyde in molratio; equal to 110 mol" 1 of phenol toj.8 3 .0 mols of formaldehyde preferably-the; ratio is 1.010 1.5-2.5 respectively, under alkaline cata lyzed conditions to provide a reaction mixture which is a water-dilutable condensate of phenol-formaldehyde hav-' ing, the, above proportions as 1 constituents: 21A second charge of formaldehyde provided preferablyatinitiation of the .phenol-formaldehyde:reactionshut .can added at anypointin time thereafter and preferably prior:- to or immediately. after addition 1 of .=:the; dicyandiamide' which latter must. be .added after initiation of thetphen'oh formaldelrryrie reaction. The :amountuof ifor'maldehyde in th second chargewonsidered, with. relation itoxthe -di= cyandiamide.tisr..5e 2.0 .rnols of formaldehyde to.71.O- =molof. dicyandiamide, with 1 .2 1 .6.-. molsiof; formaldehyde pertmol of Adicyandiamide havingibeen; found :the' more attractive. Generally, it is desirable to add '-the;.dicyandiamide at or near the end of. phenolformaldehyde reaction to the formationofinter condensates of phenolforn aldehyde -dicyandiamide reaction products which are The-reaction temperatures.prescribed-for:reacting the i phenokformaldehyde =to; fornrwa:.--water'-dilutabl partial-* condensateg thereof range ebetween 40-100 C? Wit h -the further preferencesof560430? Gw-Alkaline-catalyzed conditions are also prescribed with the preference such that the pH lies between 8.0l0.0t-:- I3hetcatalysts which can be ir 1clude sodium hydroxide, calcium hydroxide, 7

' potassium hydroxide, etc.

0 densateis lowered to arrest further more The second stage reaction that'of the formaldehyde and dicyandiamide can be carried out under temperature conditions set forth above; however, the pH conditions are more liberal allowing a -ran'g'e of 5.0-l0,0 to be exer'cis'ed "with, however, the further preference directed to7.0- 9.0. v

In a'preferred embodiment the process'isinitiated with phenol and both charges of formaldehyde-present." P'I 'he reaction isv carried duturitil [predetermined formaldehyde content remains asdet'ermined by the hydroxylamine hydrochloride test." At this point, the mixture is cooled to 3 0. 5 0 "1 ".Crrand --the"dicyai1tiianiide 'added-,followed by subjection to reaction tempe'rature to'al'low reaction of the formaldehyde and dicyandiamide to form a waterdilutable condensate thereof in situ with alwatrdilutable condensate of"phenol-formaldehyde. The temperature, time and desired magnitude of water-dilu'tabilityof the product are" interrelated? Higher temperatures and; longer periods "of timeiot reaction'will diminish water dilutability by 'causing'the formation of a copolymer of theithree' constituents, 'formaldehydefphenol and theyandiamide; or possibly of high molecular weight'phenolformaldehyde" and "dicyandiamide -formaldehyde cocondensate reaction products." "Atthe other "extreme reacting, between the formaldehyde 'andftheffdicyanjdiamid'eiinust be facilitated. Accordingly, a the particular occasion will dictate the magnitude of water-diliitabilit'y desirable in the admixed'pro'duct and thisfin'turn'will determine the time-temperature relationship to "be" exrcised,i limited howeverto thetemperature ranges setforth' abov'el' I 'h'e time forreaction of the second 's't'ageor' dicyiandiarnide formaldehyde 'cari'be determined"byuse" of "the; water dilutability test as previously described inEXarripleIand hyde'reaction.

used with reference to the first stage or phenoltorrnal de v When the reaction'has: heenfcarried out point I where desirable reaction product 'o'f'dicyan'diamideffornialdehyde is obtained; "the temperature of the" reaction mixture and correspondingly thefreSultfant' parfial "conr condensation; 'Ihetemperaturenee tl oiily'be lower obtained bydowering theternperatures to 2040" Q. or roor'ntemperature. i

Various catalysts can a'lso he irsed the second stage,

such as-sodium;- calcium, potassium, Ii hydroxides; 'etc'., which canb'e neutrali I sulfuric," boric,- phosphoric other acids *The amount ofplien't' l foi'nifa'ldehy'de r which is obtained-"admixed withtlie dic completed. Theresultin g adnfifixed r sin products stable and can" 'be handled-like etdmarythenofi-c' liquid resins. The amount of dicyandiamide fornialdehyde partial condensate 'in 'the resulting liquid-resin product Canran e u to 50% by might er-"solids; i

content of -drcyandiamrde-formaldeliyde partial sate present will contribute ?greater" heat resistan; resistant and flame-retardant properties to thv product; Y

Proportions of greater thanp30% vwill suffer from poorer stability- The resins which from exercise of the present invention can be shipped. and storedaas a -single-packa'ge-- for later use as binders in applications requiring punkresistance, heat resistance orflaineretardance properties. No modificationin equipment as "to iitilizationisrequird.

sives, bindings and the like.

V r an, 55cc tiveamounfijin this ,resp'ect'desirable' results have been It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efiiciently attained and, since certain changes may be made in carrying out the above process or method without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A process for producing water-dilutable fusible liquid resin compositions comprising a mixture of dicyandamide-formaldehyde partial condensates and phenol-formaldehyde reaction products which comprises reacting in mol ratio 0.5-2.0 mols of formaldehyde and 1.0 mol of dicyandiamide in the presence of alkaline catalyzed fusible reaction products of phenol-formaldehyde being in mol ratio of 1.0 mol of phenol to 0.8-3.0 mols of formaldehyde at a pH of between 5-10 and a temperature of 40-100" C. until a water-dilutable liquid partial condensate of dicyandiamide and formaldehyde is formed.

2. A process for producing water-dilutable fusible liquid resin compositions comprising a mixture of dicyandiamide-formaldehyde partial condensates and alkaline catalyzed phenol-formaldehyde reaction products which comprises reacting in mol ratio 0.5-2.0 mols of formaldehyde and 1.0 mol of dicyandiamide in the presence of said reaction products at a pH of between 7.0-9.0 and a temperature of 60-80 C. until a water-dilutable liquid partial condensate of dicyandiamide and formaldehyde is formed, said reaction product being in mol ratio of 1.0 mol of phenol to 0.8-3.0 mols of formaldehyde.

3. The process according to claim 2 wherein the partial condensate contains in mol ratio 1.2-1.6 mols of formaldehyde per 1.0 mol of dicyandiamide.

4. A process for producing Water-dilutable fusible liquid resin compositions comprising a mixture of dicyandiamide-formaldehyde partial condensate and alkaline catalyzed phenol-formaldehyde reaction products which comprises reacting in mol ratio of 1.2-1.6 mols of formaldehyde and 1.0 mol of dicyandiamide in the presence of said reaction products at a pH of 7.0-9.0 and a temperature of 60-80 C. until a partial condensate of dicyandiamide and formaldehyde is formed, said reaction products being in mol ratio of 1.0 mol of phenol to 1.5-2.5 mols of formaldehyde.

5. An aqueous-solvated, liquid, Water-dilutable, fusible dicyandiamide-formaldehyde resin composition in single package form adapted for shipping and storing thereof and exhibiting improved water-dilutability retention, the said composition comprising an aqueons-solvated, liquid, water-dilutable, fusible mixture of condensates of dicyan diamide-formaldehyde and phenol-formaldehyde of the type resulting from reacting 1.0 mol of dicyandiamide and 0.5-2.0 mols of formaldehyde in mol ratio in the presence of an alkaline-catalyzed water-dilutable reaction mixture of phenol-formaldehyde at a pH of 5.010.0 and a temperature of 40-100 C. until a water-dilutable,

liquid partial condensate of dicyandiamide and formaldehyde is formed as determined by the said partial condensate phobing in a quantity of water, the said phenolformaldehyde reaction mixture being constituted of 1.0 mol of phenol to 0.8-3.0 mols of formaldehyde in mol ratio.

6. A method for preparing a resin composition having improved stability so as to render it suitable for shipping and storing which resin composition comprises aqueoussolvated, liquid, water-dilutable, fusible dicyandiamideformaldehyde resin condensates exhibiting improved Water-dilutability retention which method comprises providing the said condensate in the form of an aqueoussolvated, liquid, water-dilutable, fusible mixture of condensates of dicyandiamide-formaldehyde and phenolformaldehyde of the type resulting from reacting 1.0 mol of dicyandiamide and 0.5-2.0 mols of formaldehyde in mol ratio in the presence of an alkaline-catalyzed, waterdilntable reaction mixture of phenol-formaldehyde at a pH of 5.0l0.0 and a temperature of 40-100 C. until a water-dilutable, liquid, partial condensate of dicyandiamide and formaldehyde is formed as determined by the said partial condensate phobing in a quantity of water, the said phenol-formaldehyde reaction mixture being constituted of 1.0 mol of phenol to 0.8-3.0 mols of formaldehyde in mol ratio.

7. A heat-resistant, punk resistant and flame retardant thermoset product obtained by curing an aqueous-solvated, liquid, water-dilutable, fusible dicyandiamide-formaldehyde resin composition in single package form adapted for shipping and storing thereof and exhibiting improved water-dilutability retention, the said composition comprising an aqueous-solvated, liquid, water-dilutable, fusible mixture of condensates of dicyandiamide-formaldehyde and phenol-formaldehyde of the type resulting from reacting l.0 mol of dicyandiamide and 0.52.0 mols of formaldehyde in mol ratio in the presence of an alkalinecatalyzed water-dilutable reacton mixture of phenolformaldehyde at a pH of 5.0l0.0 and a temperature of 40-100 C. until a water-dilutable, liquid, partial condensate of dicyandiamide and formaldehyde is formed as determined by the said partial condensate phobing in a quantity of water, the said phenol-formaldehyde reaction mixture being constituted of 1.0 mol of phenol to 0.8-3.0 mols of formaldehyde in mol ratio.

References Cited in the file of this patent UNITED STATES PATENTS 2,604,427 Armstrong et al. July 22, 1952 2,737,504 Dawson et al. Mar. 6, 1956 FOREIGN PATENTS 498,165 Great Britain Jan. 4, 1939 59,027 Russia Feb. 28, 1941 OTHER REFERENCES Serial No. 237,057, publication of Greth (A.P.C.), published April 20, 1943, now abandoned. 

5. AN AQUEOUS-SOLVATED, LIQUID, WATER-DILUTABLE, FUSIBLE DICYANDIAMIDE-FORMALEDHYDE RESIN COMPOSITION IN SINGLE PACKAGE FORM ADAPTED FOR SHIPPING AND STORING THEREOF AND EXHIBITING IMPROVED WATER-DILUTABILITY RETENTION, THE SAID COMPOSITION COMPRISING AN AQUEOUS-SOLVATED, LIQUID, WATER-DILUTABLE, FUSIBLE MIXTURE OF CONDENSATES OF DICYANDIAMIDE-FORMALDEHYDE AND PHENOL-FORMALDEHYDE OF THE TYPE RESULTING FROM REACTING 1.0 MOL OF DICYANDIAMIDE AND 0.5-2.0 MOLS OF FORMALDEHYDE IN MOL RATIO IN THE PRESENCE OF AN ALKALINE-CATALYZED WATER-DILUTABLE REACTION MIXTURE OF PHENOL-FORMALEDHYDE AT A PH OF 5.0-10.0 AND A TEMPEATURE OF 40*-100*C. UNTIL A WATER-DILUTABLE, LIQUID PARTIAL CONDENSATE OF DICYANDIAMIDE AND FORMALDEHYDE IS FORMED AS DETERMINED BY THE SAID PARTIAL CONDENSATE PHOBING IN A QUANTITY OF WATER, THE SAID PHENOLFORMALDEHYDE REACTION MIXTURE BEING CONSTITUTED OF 1.0 MOL OF PHENOL TO 0.8-3.0 MOLS OF FORMALDEHYDE IN MOL RATIO. 